From dermoscopedia

In this chapter we describe the dermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections. term hyperpigmented structureless areablotch If centric hypermelanotic Clark (“dysplastic”) nevus if eccentric melanoma (blotchDark structureless areas) and its histopathological correlation

A blotch is defined as an area with a size that is at least 10% of the lesion’s surface area and is heavily pigmentedThis glossary term has not yet been described.. In a blotch the melanin pigment is often present throughout the skinThis glossary term has not yet been described., including the stratum corneum, epidermis, and the dermis [1]. The dark pigment in a blotch visually obscures the ability to discern any underlying structuresThis glossary term has not yet been described.[2]. Blotches can be regular or irregular.

Regular blotches are defined as those that display symmetry, regular borders,homogenous dark hue, and are located within the center of the lesion. A pigment networkThis glossary term has not yet been described. often surrounds a regular blotchOne blotch within center of lesion and surrounded by network. Regular blotches are associated with neviThis glossary term has not yet been described..

Regular blotches can be seen in “activated” nevi and are attributed to heavy melanin concentrations in the stratum corneum. Because the pigment is concentrated in the stratum corneum, it can easily be stripped off using a tape-stripping procedure, thereby revealing underlying structures.

Irregular hyperpigmented structureless area (Blotch)

Irregular blotches are defined as those that are asymmetric, have irregular contours, are located off center, and/or display multiple dark hues (i.e., heterogenous dark hues). Irregular blotches are associated with melanomaThis glossary term has not yet been described. or dysplastic nevusThis glossary term has not yet been described..

ReferencesThis is material contained in a footnote or bibliography holding further information.

↑Kittler et al.: Standardization of terminology in dermoscopy/dermatoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.: Results of the third consensus conference of the International Society of DermoscopyThe examination of [skin lesions] with a 'dermatoscope'. This traditionally consists of a magnifier (typically x10), a non-polarised light source, a transparent plate and a liquid medium between the instrument and the skin, and allows inspection of skin lesions unobstructed by skin surface reflections. Modern dermatoscopes dispense with the use of liquid medium and instead use polarised light to cancel out skin surface reflections.. J. Am. Acad. Dermatol. 2016;74:1093-106. PMID: 26896294. DOI.